Apparatus for producing composite fibers

ABSTRACT

A SPINNING HEAD FOR MELT SPINNING OF COMPOSITE FILAMENTS COMPRISED OF TWO POLYMERS OF EQUAL SEMI-CIRCULAR CROSS-SECTION IN WHICH THE MATING FACES OF A DISTRIBUTION PLATE AND A SPINNERET PLATE FORM TWO SEPARATE ANNULAR CAVITIES EACH COMMUNICATING WITH A DIFFERENT POLYMER SUPPLY CONTAINED IN THE DISTRIBUTION PLATE. A PLURALITY OF EXTRUSION HOLES IN THE SPINNERET PLATE HAVE THEIR UPPER END PORTIONS OF SEMI-CIRCULAR CROSS-SECTION COMMUNICATION WITH ONE OF THE ANNULAR CAVITIES AND THE REMAINING PORTIONS OF CIRCULAR CROSS-SECTION COMMUNICATING WITH THE OTHER ANNULAR CAVITY.

June 13, 1972 E. FERMI ETAL 3,669,591

APPARATUS FOR PRODUCING COMPOSITE FIBERS Filed March 11, 1970 3ShGGtS-Sh'it l IXVENTORS W ami June 13, 1972 E. EEEEEEE AL 3,669,591

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APPARATUS FOR PRODUCING COMPOSITE FIBERS Filed March 11, 1970 5Sheets-Sheet} United States Patent Oflice 3,569,591 Patented June 13,1972 3,669,591 APPARATUS FOR PRODUCING COMPOSITE FIBERS Enzo Fermi andFrancesco Sassanelli, San Donato Milanese, Italy, assignors to SnamProgetti S.p.A., Milan, Italy Filed Mar. 11, 1970, Ser. No. 18,563Claims priority, application Italy, Mar. 11, 1969, 13,914/ 69 Int. Cl.D01d 3/00 US. Cl. 425-131 6 Claims ABSTRACT OF THE DISCLOSURE A spinninghead for melt spinning of composite filaments comprised of two polymersof equal semi-circular cross-section in which the mating faces of adistribution plate and a spinneret plate form two separate annularcavities each communicating with a different polymer supply contained inthe distribution plate. A plurality of extrusion holes in the spinneretplate have their upper end portions of semi-circular cross-sectioncommunicating with one of the annular cavities and the remainingportions of circular cross-section communicating with the other annularcavity.

The present invention refers to new extruders suitable for obtainingcomposite fibers and filaments.

For many years, in the spinning technology of artificial and syntheticfibers, processes for obtaining composite fibers have been known whichemploy spinning devices consisting of knives for separating of thedifferent polymers in the proximity of the extrusion zone. With theseknown devices, it is possible to divide two different polymers into twogenerally concentric circular zones, each of them being situated nearthe extrusion orifices.

The aforementioned known spinning devices have, however, been subject toseveral drawbacks. In particular, difficulty has been encountered in thefield of melt spinning in obtaining composite filaments having perfectlyevenly divided cross-sections of conjugated polymers.

It is therefore an object of this invention to provide a new andimproved apparatus for forming composite fibers and filaments.

Another object of this invention is to provide, in a new and improvedapparatus for forming composite fibers and filaments, a spinneret platewhich is of simplified construction and utilization.

Briefly described, the foregoing objects of the present invention areattained by providing a spinneret plate which consists of a singlepiece, thereby reducing sealing difficulties which are generallyencountered in conventional spinning heads, which require two spinneretplates for forming conjugated fibers. The extrusion orifices of thespinneret plate are partially semi-circular and partially circular incross-section and receive the two polymers at different points, so thatthe first polymer is shaped into a semi-circular cross-section beforethe second polymer is introduced to the portion of the extrusion holeshaving a circular cross-section. Practically, it is preferable that thesemi-circular cross-sectional portion of each of the extrusion holesextends for at least 2 mm. The polymer distribution plate is an integralpart of the apparatus in that the possibility of employing the spinneretplate for forming bicomposed filaments depends on its lower face beingshaped so as to mate perfectly with the upper face of the spinneretplate.

The accompanying drawings, referred to herein and constituting a parthereof, illustrate preferred embodiments of the invention and, togetherwith the description, serve to explain the principles of the invention.

FIG. 1 represents a cross section of spinneret plate B and distributionplate A constructed according to the present invention.

FIG. 2 is a top plan view of the spinneret plate according to FIG. 1.

FIG. 3 shows a cross section of another spinneret plate 1) anddistribution plate C, according to the present invention.

4 is a top plan view of the spinneret plate of FIG. 5 is a photographicreproduction of an assembly according to the invention.

Obviously the above figures are only intended to illustrate but not torestrict the invention itself.

With reference to the above figures the hollow chamber 1 and 2 ofdistribution plate A contain two different polymers which, through thefares 3 and 4, respectively, are fed through the annuluses 5, 7,respectively, to the extrusion holes 8. As best seen in FIGS. 1 and 3,the polymer contained in chamber 1 enters extrusion hole 8 at a point 9where it is semi-circular in cross-section and the polymer contained inchamber 2 of the distribution plate enters the extrusion hole 8 at apoint where it is circular in cross-section.

Essentially the extrusion device suitable for manufacturing bicomposedfibers according to the invention consists of a spinneret plate and adistribution plate and is characterized in that the feeding of twodifferent polymers takes place at different levels with respect to thespinneret extrusion hole. One of the polymers is fed to the extrusionhole at a point where its cross-section is semi-circular in shape so asto be formed into a semicylindrical profile before reaching the portionof the extrusion hole which has a circular cross-section, where theother polymer is introduced.

The cross-section of composite fibers obtained with spinning apparatusconstructed according to the invention presents a very sharp andsubstantially straight separation line between the two components. Inaddition, it has been found that a spinning head constructed accordingto the invention permits the distribution plate to be shaped so as toenable the unit to be sealed both on the external periphery thereof andalso on its central zone which contacts the spinneret plate. Also, aspreviously mentioned, the distribution plate allows the distribution ofdifferent polymers in two different points of the spinneret plateextrusion holes by using the semi-circular cross section of the holeformed by the distribution plate for feeding a first polymer thereto andfeeding the other polymer at another half of the hole in the point wherethe complete circular cross section is reinstated.

The invention in its broader aspects is not limited to the specificembodiments herein shown and described but departures may be madetherefrom within the scope of the accompanying claims, Without departingfrom the principles of the invention and without sacrificing its chiefadvantages.

We claim:

1. A spinning head for melt spinning of composite filaments or the like,including a spinneret plate;

said spinneret plate including a plurality of extrusion holes, each ofsaid extrusion holes including a first portion of semicircularcross-section, and a second portion of circular cross-section; adistribution plate including a first chamber, a first passagewayextending out of said first chamber,

a second chamber, and

a second passageway extending out of said second chamber; first annularcavity means being defined by said spinnert and distribution plates andcommunicating said first passageway extending out of said first chamber5 with said first semi-circular portions of each of said extrusionholes; and second annular cavity means being defined by said spinneretand distribution plates and communicating said second passagewayextending out of said second chamber to said second circular portions ofeach of said extrusion holes. 2. A spinning head as claimed in claim 1,wherein said spinneret plate is formed on one face thereof with a firstannular rib member; said distribution plate is formed on one facethereof with a first annular recess communicating with said firstpassageway,

said first annular recess adapted to telescopically slida-bly receive aportion of said first annular rib member formed on said spinneret plateso as to form said first annular cavity means; said distribution platehaving further formed on said one face thereof a second annular recessopening at one side into said first annular recess 5 and communicatingwith said second passagey, said second annular recess adapted to formwith said one face of said spinneret plate said second annular cavitymeans; and said extrusion holes are formed in said spinneret plate sothat their central axes are in registry with the inner edge of saidfirst annular rib member,

whereby the inner side wall of said first annular recess forms saidfirst semi-circular portion of 35 said extrusion hole. 3. A spinninghead a claimed in claim 1, wherein said semi-circular cross-sectionalportion of each of said extrusion holes extends for a length of at least2 mm.

4. A spinning head as claimed in claim 2, wherein said first annular ribmember is stepped along the inner circumferentially-extending edgethereof; and

4 said spinneret plate has an annular step formed opposite said secondannular recess in said distribution plate and extending along the outerportion thereof; whereby said first and second annular cavity means eachinclude narrowed portions adjacent said extrusion holes. 5. A spinninghead as claimed in claim 2, wherein said first annular recess is boundedon its outer edge by the peripheral portion of said distribution plateso as to form a circumferentially-extending outer rib; and saidspinneret plate includes a circumferentially-extending groove adjacentsaid first annular rib member and extending along the peripheral edge ofsaid spinneret plate,

whereby said circumferentially-extending outer rib member of saiddistribution plate is adapted to sealingly mate with saidcircumferentiallyextending peripheral groove on said spinneret plate. 6.A spinning head as claimed in claim 5, wherein said distribution plateincludes a central portion in wardly of said second annular recessadapted to sealingly engage said spinneret plate.

References Cited UNITED STATES PATENTS 3,017,686 1/1962 Breen et a1264-477 FX 3,075,241 1/1963 Dietzsch et al 188 SC 3,188,689 6/1965 Breen18-8 SC FOREIGN PATENTS 1,101,452 1/1968 Great Britain 18-8 SC I.SPENCER OVERHOLSER, Primary Examiner M. O. SUTTON, Assistant ExaminerUS. Cl. X.R.

Patent No. 3,669,591 Dated June 13, 1972 Inventor(s) Enzo Fermi andFrancesco Sassanelli It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Signed and sealed this 19th day of March 19774..

(SEAL) Attest:

EDWARD M.FLETCHER, JR. C. MARSHALL DANN Attesting Officer Commissionerof Patents Column 1, line 32, after "separating" delete of Column 2,line 17, change "fares" to read bores line 50, change "another" to readother Column 3, line 37, after "head" change "a" to as FORM PO-1050(10-69) USCOMNFDC corned a u.s. sovlmmnn rnnmna ovncz: n0 o-au-a

